1. Field of the Invention
The present invention relates to a method and apparatus for forming the top of a container. Specifically, the present invention relates to a method and apparatus for forming the top of a container on a mandrel wheel of a form, fill and seal packaging machine.
2. Description of the Related Art
Many varieties of single-use containers exist for the packaging of liquids, powders or the like. The liquids may include milk or juice. The containers may be formed from blanks or sheets made of a variety of laminate materials having a substrate such as paperboard, strawboard, pasteboard, cardboard, and the like. The substrate may be laminated with a thermoplastic or similar liquid resistant coating to enable the container to retain liquids. The blanks may be folded into a variety of container cross-sections, such as tubular, rectangular, square, octagonal, hexagonal, and the like.
Traditionally, milk has been packaged in gable-top cartons that are torn open to reveal an integrated pouring device for accessing the product. Most recently, juice, such as orange juice, packaged in gable-top cartons with a fitment attached for accessing the product has gained favor with the consumer.
However, gable-top cartons have limitations that are dependent upon the circumstances. Gable-top cartons waste an enormous amount of material to form the gable-top that before the advent of fitments, and the technology for applying them, was necessary to access the product. Currently, with the popularity of fitments, the gable-top has become a non-functional aesthetic component of cartons.
Conventional containers have been proposed with flat upper ends having a spout and cap opening in the center of the top. However, flat-ended containers experience other limitations. In flat-ended containers, the adjoining edges of the folded end panels produce seams. These seams expose edges of the paperboard substrate material to the liquid product within the container. The product undergoes a wicking or capillary action and is soaked into the paperboard core of the container thereby degrading the seals and compromising the integrity of the package. In addition, conventional flat-ended containers are unable to achieve a hermetic seal along the seams produced at the upper end of the container. Thus, while conventional flat-ended containers are liquid tight, such containers are not hermetically sealed and, therefore, are unable to maintain a pressurized interior chamber, such as is required to preserve carbonated liquids. In addition, the non-hermetic seams in conventional paperboard-based containers are an unsatisfactory medium for storing liquids which are highly sensitive to oxygen, such as wine, orange juice, or the like.
A further problem has been forming containers without a top fin seal most readily apparent on a gable-top carton. For the most part, traditional form, fill and seal carton packaging machines do not lend themselves to high production of non-gable-top cartons. Some machines may flatten and seal the gable-top to provide an appearance of a flat top carton; however, this does not resolve the inefficient use of material.